Design And Simulation Research On The Five Degrees-of-freedom Air Bearing Platform Control System Based On XPC

China’s successful launch of "Tiangong-1" and the successful completion of themission that shenzhou8has been rendezvoused and docked with shenzhou9, marksChina’s space industry entered a new strategic stage. The development and perfectionof space rendezvous and docking technology can effectively guarantee theestablishment of a space station and the completion of space experiments. Therendezvous and docking mission requires a lot of manpower and material resources, sothe ground docking simulation platform is to simulate space rendezvous and dockingmission and to verify important means of the control strategy. The main work of thispaper is to set up and implement various function modules of5-DOF air simulationplatform, for the attitude control, this paper designs the sliding mode controller, studiesthe control allocation, and verifies the simulation.First,in this paper,introduces the working principle of5-DOF air platform and theoverall scheme design of control system, expounds working principle and compositionof each functional module of the air platform, completes the actual test.Set up theground monitoring interface and complete communication between the groundmonitoring computer and satellite-borne computer.Secondly, according to knowledge of the rigid body dynamics and kinematics, setup dynamic model of5-DOF air platform dynamics and kinematics model based onerror quaternion. Calculate rotational inertia matrix of the air platform, and conciselyanalyze the air platform bear the disturbance power and disturbance torque in the actualsituation, provide a theoretical basis for the design of the attitude controller andsimulation.Again, the paper expounds the related theory of sliding mode ariable structure,according to the requirement of attitude control of the air platform, designs thetraditional sliding mode variable structure controller,fast terminal sliding modecontroller and nonsingular terminal sliding mode controller respectively,at lastsimulation work has been carried out.Finally，due to the problem that executive body of5-DOF air platform existsredundance, the corresponding control allocation strategies have been designed. Themathematical description of control allocation of5-DOF air platform is given. Inaddition, the researches of control allocation method and control switch issues havebeen taken and simulated.